ex.: Parallel
1
0
1
0
0
0
0
1
A0
A1
A2
A3
D0
D1
D2
D3
Addresses and data are processed in parallel.
[Advantage] Fast processing
ex.: Serial
Addresses and data are processed in serial.
A:0101
D:1100
D0
:1100
A1
[Advantages]
The size can be reduced due to the
reduced number of I/O terminals, and
fewer wires are required for the substrate.
The package can be downsized and manufactured inexpensively.
2. 3-wire type, microwire, 4-wire type
Composed of four pins, including three input pins CS, SK, and DI, and an output pin DO. Since DI
and DO can be directly coupled together, the EEPROM can be virtually composed of three pins (the
4-wire type includes an additional Ready/Busy pin, but is still referred to as a “3-wire type”).
NS code: The key word is “93Cx.” Compatible with SII S-29xxOA.
General code used by many competing companies. Mass produced and low in cost.
GI code
General Instrument Inc.’s original code. Its markets continue to dwindle.
Mitsubishi code: The key word is “M6M8.”Compatible with SII S-29x55A. Serial-port direct-coupling
type in which commands and data are composed of x8 units. Intended for the TV and VTR markets
and primarily sold as a set with Mitsubishi microcomputers.
SII original code: S-29x9xA
Serial-port direct-coupling type in which commands and data are composed of x8 units. Intended
for technology-oriented users.
3. 2-wire type, IICBUS: The key word is “24C.” Compatible with SII S-24CxxA. Composed of two
pins: an input pin (SCL) and an I/O pin (SDA). Phillips Inc. owns a relevant patent.
[Advantages]
Fewer wires are required, and the microcomputer port can be shared with
another IICBUS. TV set maker will be main market.
4. SPI: The key word is “25C.” Not compatible with SII. Under development. Composed of four pins:
three input pins CS, SCK, and SI, and an input pin SO. In the case of the EEPROM, the
advantages are high speed (5 MHz at 5v) and a high capacity (128 Kbytes).
<Remarks>
FAQ No.: 12004
47
SII [ SEIKO INSTRUMENTS INC ]
